The bane of the sailor, barnacles are an opportunistic small animal that has carved out a unique niche in the underwater world. It’s not a mollusk like a clam or mussel as commonly thought, but a crustacean like a crab or lobster.

While there are over 1200 species of barnacles, which are found all over the world, the barnacle is particularly meddlesome in the Chesapeake Bay, the sailing capital of the nation. Boaters spend millions on keeping them from attaching themselves to boat bottoms. Just a gallon of marine anti-fouling paint costs about $250. But special paint is only a temporary measure. Eventually the paint becomes less effective and plant and animal growth begins. Once or twice a season, boats must have their bottoms cleaned.

A boat with a fouled bottom is analogous to swimming with your overcoat on. It can take as much as twice the energy to move it through the water. The larger the boat or ship, the costs go up exponentially.

But as much as sailors detest them, the lowly barnacle is a fascinating little creature. Each has both male and female organs, but its eggs must be cross-fertilized by a neighbor barnacle. A sperm tube extends from one into another to fertilize its eggs. Once hatched, the microscopic larvae are then released into water to join the planktonic drift.

Larvae go through two molting stages, lasting only a few days, and then search out a place to attach themselves, usually among adult barnacles of the same species. The cement-like substance they use to make this attachment is being studied. It would be of tremendous value to the dental arts community to find a strong bonding agent that works well in a wet environment.

Most larvae are consumed before they can find a suitable home. They are eaten by small fish and filter feeders like oysters and muscles. Those that become attached, soon develop the familiar shell plates that eventually cover their body. They grow by adding calcium carbonate to the edges of their shell plates. The interior barnacle grows by shedding its exoskeleton, just as a blue crab or other crustacean does.

Happily attached to a hard surface, the barnacle feeds by opening its “trap doors” pushing out feathery appendages (its adapted legs) to emerge from inside and sweep in tiny particles of plankton and detritus.

While annoying and even costly to the boater, the barnacle has been around for many millions of years and is expected to be here for some time to come. So the battle will continue, yet the outcome is already known.

For more Chesapeake Bay articles by this author, see:  The Chesapeake , The Blue Crab , The Oyster , The Eagle ,  Great Blue Heron , The Osprey

© 2010 Consumer Guide, by David Sullivan